The good, the bad, and the buggy: A useful primer on antibiotic resistance, with two pages of illustrations, explains how bacteria develop resistance and pays special attention to the spread of methicillin-resistant Staphylococcus aureus (MRSA) from hospitals into the community, development of resistance in and around concentrated animal feeding operations (CAFOs), emissions from antibiotic manufacturing facilities, and from human use. CAFOs rely on antibiotics to keep animals healthy in their stressful environment and also to improve growth rates. Research shows that animals excrete significant amounts of antibiotics unchanged, contributing to the evolution of resistant pathogens in animal-waste holding areas. The article concludes with a summary of the efforts directed toward reducing antibiotic misuse and development of new drugs. (Environmental Health Perspectives)